Bimetallic coin

ABSTRACT

A coin is disclosed having a middle layer of aluminum clad on its opposite major faces with stainless steel. The aluminum layer has a thickness corresponding to 80 to 95 percent of the combined thickness of the three layers. The color differential between the layers is minimal since all layers have substantially the same light reflective properties.

United States Patent [56] References Cited Inventor Brian G. HarrisonDrexel Hill, Pa. AppL No 858,689 UNITED STATES PATENTS Filed Sept. 17,1969 2,782,498 2/1957 MUSllOVlC et al 29/497.5 patented Sept 21 19713,031,330 4/1962 l-lornrck 117/46 Assignee The Franklin Mint, Inc,3,210,840 10/1965 Ulam 29/488 yeadon, Pm 3,261,724 7/1966 Ulam 148/1153,462,827 8/1969 Winter 29/472.3 3,496,621 2/1970 Winter 29/] 83.5

.. Primary Examiner-L. Dewayne Rutledge Assistant ExaminerE. L WeiseAttorneySeidel, Gouda and Goldhammer BIMETALLIC COIN 3 Clam 2 Draw";ABSTRACT: A coin is disclosed having a middle layer of alu- U.S. Cl.29/191, minum clad on its opposite major faces with stainless steel. 29/196.2 The aluminum layer has a thickness corresponding to to Int. ClA44c 21/00 percent of the combined thickness of the three layers. TheField of Search 29/1962, color differential between the layers isminimal since all layers 191, 183.5, 40/27.5 have substantially the samelight reflective properties.

PATENTEDSEPZ] |97| 147 FIG. 2

IN l/E N TOR BRIAN 6- HARRISON A TTORNEYS.

BIMETALLIC COIN This invention relates to a bimetallic coin which islight in weight, has good wear characteristics, and has a good feel. Thethin layer of stainless steel is clad to the opposite surfaces of alayer of aluminum, typically by the application of heat and pressure.The aluminum layer has a thickness corresponding to 80 to 95 percent ofthe combined thickness of the three layers.

As used herein, the word aluminum is to be interpreted as includingaluminum alloys. The stainless steel and aluminum layers havesubstantially the same light reflective properties whereby the colordifferential is nondistinctive and thereby unobjectionable. The coin islight in weight due primarily to the aluminum layer. As used herein, theword coin" is intended to encompass nonmonetary tokens, medallions,gambling chips, commemorative coins, etc.

It is an object of the present invention to provide a coin which hasgood wear characteristics, resists corrosion, is lighter in weight thanmost coinage, but nevertheless retains acceptable feel."

It is another object of the present invention to provide a coin whichaccomplishes the above-identified object by using a sandwich of aluminumand stainless steel.

it is another object of the present invention to provide a bimetalliccoin wherein the layers thereof have substantially the same lightreflective properties.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1 is a plan view of a coin in accordance with the presentinvention. 1

FIG. 2 is a sectional view taken along the line 22 in FIG. 1.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIG. 1 a coin designated generally as 10.The coin may have any commemorative figure or other configuration 12applied to one surface thereof. The other surface of the coin may have asimilar configuration or a different configuration 14 and/or explanatorywording.

The coin 10 is bimetallic and comprises a middle layer of aluminum, atop layer 18 of stainless steel, and a bottom layer of stainless steel.The layers 16-20 have substantially the same light reflectiveproperties. Layer 16 has a thickness of between 80 and 95 percent of thecombined thickness of all of the layers. Preferably, the layer 16 has athickness of 90 percent of the combined thickness with each of thelayers 18 and 20 having a thickness of approximately 5 percent of thecombined thickness of the coin 10.

The layer 16 renders the coin 10 light in weight. The stain less steellayers 18 and 20 provide for good wear characteristics and provide thecoin 10 with a good feel. The coin 10 preferably has a milled periphery22. The milled periphery 22 helps to break up the light and render theinterface between the layers difficult to discern, in view of the factthat the layers are substantially the same color.

The hardness of the stainless steel layers 18 and 20 is substantiallyhigher than normal for coinage alloys. lndeed, the material used in thelayers 18 and 20 would normally be uncoinable. The aluminum layer 16,however, allows for stretching and bending of the layers 18 and 20during coining, and itself undergoes the bulk of the deformation. Hence,the coin is equivalent in hardness and wear properties to hardrolledstainless steel. in addition, a U.S. cost is realized as compared withmost coinage alloys.

The layers 18 and 20 of stainless steel are preferably clad to thealuminum layer 16 in sheet form under heat and pressure, typically byrolling. Suitable parameters for cladding the stainless steel to thealuminum include a pressure of approximately 20,000 p.s.i. at atemperature of approximately 850 F. The layers 18 and 20 may be clad tothe aluminum layer 16 in the manner taught by U.S. Pat. No. 2,782,498,issued Feb. 26, I957. Thereafter, the sheets may be transformed intocoins by a conventional coining press. By way of illustration and not byway of limitation, the coin 10 may have a combined thickness of 0.06inch with layer 16 having a thickness of approximately 0.054 inch witheach of the layers 18 and 20 having a thickness of approximately 0.003inch. As will be apparent from FIG. 2, the contour of the configurations12 and 14 have a height greater than the thickness of either of thelayers 18 and 20 whereby the middle layer 16 is deformed so as tocorrespond to the configurations l2 and 14.

The present invention may be embodied in other specific fonns withoutdeparting from the spirit or essential attributes thereof.

1 claim:

1. A coin comprising a middle layer of aluminum sandwiched between cladlayers of stainless steel, the thickness of said middle layer beingbetween and 95 percent of the combined thickness of said three layers,at least one major face of the coin having a configuration thereonpartially formed in the middle layer, and said layers havingsubstantially the same light reflective properties.

2. A coin in accordance with claim 1 wherein said middle layer has athickness of percent of the combined thickness of said three layers,each of the layers of stainless steel being of substantially the samethickness 3. A coin in accordance with claim 1 including a milledperiphery on said layers.

1. A coin comprising a middle layer of aluminum sandwiched between cladlayers of stainless steel, the thickness of said middle layer beingbetween 80 and 95 percent of the combined thickness of said threelayers, at least one major face of the coin having a configurationthereon partially formed in the middle layer, and said layers havingsubstantially the same light reflective properties.
 2. A coin inaccordance with claim 1 wherein said middle layer has a thickness of 90percent of the combined thickness of said three layers, each of thelayers of stainless steel being of substantially the same thickness
 3. Acoin in accordance with claim 1 including a milled periphery on saidlayers.